An Unfolding Scientific Revolution in Cosmology | Hacker News Reader

An Unfolding Scientific Revolution in Cosmology

economicsfromthetopdown.com

28 pointsmatusp8 comments

> In hindsight, the ‘seemingly’ part is key. When astronomers first gazed beyond the solar system, they noticed systematic deviations from the predictions of Newtonian gravity. Most scientists assumed that the problem was due to missing mass. But today, there is mounting evidence that this hypothesis is false, and that the observed discrepancy is caused by a breakdown of Newtonian physics. However, like the geocentric model of antiquity, the dark-matter paradigm lumbers on as the dominant belief, largely unfazed by the challenging evidence.

Yeah given that this blog is about "new ideas in economics and the social sciences" I was already feeling a bit skeptical, but when I got to this point and saw no mention of https://en.wikipedia.org/wiki/Bullet_Cluster (I did not bother looking at the 4-year-old video linked to in that paragraph), I had to put this piece down. I subscribe to a number of astronomy youtubers and I have not heard anyone with data to back them up making this assertion.

As a counterpoint example, here's Dr. Becky (https://www.physics.ox.ac.uk/our-people/smethurst) from ~4 months ago obviously not coming from the perspective that dark matter is being ruled out, and right out of the gate she refers back to another piece talking about why we are (so far) convinced dark matter is legitimate: https://www.youtube.com/watch?v=lyyZzzgoLNE

So, yeah, as jfengel says...this seems like more MOND again from a dilettante. Skip it

I heard the perspective from one astronomer that "dark matter" isn't a theory so much as an observation (and same goes for dark energy)

Heh https://www.youtube.com/watch?v=PbmJkMhmrVI

Some critical feedback

https://www.reddit.com/r/AskPhysics/comments/1lj2k88/comment...

Tl;dr it's MOND again.

I has to look it up, yes I remember MOND now, thanks

For others:

https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics

The preamble was so long, I actually gave up and came here for a TL;DR, and here it is ! :-D

Why do some people write blogs as if they're still being paid per word ?!

Even Wikipedia article [1] on the rotation curves mentioned that those could be explained if one stops using Newtonian mechanics and rather try to use the full equations of General Relativity. Basically it turned out on the galaxy scale one could not use Newtonian approximation. GR equations are highly non-linear and even tiny non-Newtonian effects accumulates.

Then there are various articles pointing out that taking into account that galaxies are filled with plasma can also explain observed results.

[1] - https://en.wikipedia.org/wiki/Galaxy_rotation_curve

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